Workpieces, including food products, are portioned or otherwise cut into smaller units or portions in accordance with customer needs. Food products are commonly portioned either to uniform or specific sizes, weights, thicknesses, or other specifications. Examples of commonly portioned food products include steaks to be served in restaurants, chicken filets packaged in frozen dinners and chicken patties sized and shaped to fit within a specific bun. Fish is likewise routinely portioned into filets or steaks.
Much of the portioning of workpieces, and in particular food products, is now carried out with the use of high-speed portioning machines. These machines use various scanning techniques to ascertain the size, shape, and other physical characteristics of the workpiece as it is being advanced on a moving conveyor. This information is analyzed with the aid of a computer to determine how to most efficiently portion the workpiece into optimum or desired sizes, weights, thicknesses, or other criteria being used. For example, the customer may desire chicken breast portions in two different weights or sizes. The chicken breast is scanned as it moves on an infeed conveyor belt, and a determination is made through the use of the computer as to how best to portion the chicken breast to the specific weights desired by the customer.
Portioning of workpieces can be performed by a cutting blade that swings across the conveyor system through a gap defined by the ends of two adjacent conveyors that advance and support the workpieces being portioned. Typically, the blade is attached to a servo motor, which spins the blade very quickly through the gap. The workpiece progresses forwardly on the conveyor belts across the gap, thereby advancing between successive blade revolutions. The blade may make approximately 20 to 30 cuts per second to provide controlled weight, thickness, or size portions, and the timing of the blade passage through the conveyor belt gap must be very tightly controlled.
As discussed below, it is important to optimize the speed of the rotating blade cutter to achieve clean and accurate cuts of the workpieces while also maximizing throughput and minimizing heat generation in the servo motor. The present disclosure addresses methods and systems for optimizing the rotational speed of the portioning blade.